models/repo: fix SQLite3 database-lock when fail to delete repository (#4048)

models/repo.go

@@ -1414,6 +1414,10 @@ func DeleteRepository(uid, repoID int64) error {
 		return err
 	}
 
+	if err = sess.Commit(); err != nil {
+		return fmt.Errorf("Commit: %v", err)
+	}
+
 	// Remove repository files.
 	repoPath := repo.repoPath(sess)
 	RemoveAllWithNotice("Delete repository files", repoPath)
@@ -1425,10 +1429,6 @@ func DeleteRepository(uid, repoID int64) error {
 		RemoveAllWithNotice("Delete attachment", attachmentPaths[i])
 	}
 
-	if err = sess.Commit(); err != nil {
-		return fmt.Errorf("Commit: %v", err)
-	}
-
 	if repo.NumForks > 0 {
 		if _, err = x.Exec("UPDATE `repository` SET fork_id=0,is_fork=? WHERE fork_id=?", false, repo.ID); err != nil {
 			log.Error(4, "reset 'fork_id' and 'is_fork': %v", err)